1. Field of the Invention
The present invention relates to the manufacture of laminated glazings in glass and/or plastic, for example large-sized laminated glazings, such as glazings for automobiles or buildings, and small-sized glazings for masks, screens, eyeglasses, etc. More particularly, the invention relates to a new adhesive layer used in the manufacture of such laminated glazings. Furthermore, it relates to laminated glazings containing said adhesive layer.
2. Background of the Prior Art
The use of a polyurethane layer, for example, as an adhesive layer in laminated glazings is well-known and is described in numerous patent publications. This layer can fulfill the sole function of adhesive. It can in addition play the role of an energy-absorber.
This adhesive layer can be used to assemble sheets of various glass and/or plastic substances.
Depending on the components to be assembled and the uses planned for the laminated glazings, it is desired to have greater or lesser adhesion between the components to be assembled and the inserted layer. When greater adhesion is desired, it is generally necessary to treat the components to be assembled using a primer, so as to increase the natural adhesion of the polyurethane layer with the glass or plastic sheets.
Finding a suitable primer is not easy and, when such is found, it can generally only be applied to a specific polyurethane layer.
Problems of adhesion can thus be posed for other intermediate layers for laminated glazings, in particular for polyvinyl chloride (PVC) or polyvinylbutyral (PVB) intermediate layers.
Thus, high optical quality transparent polyvinyl chloride could be used to advantage as an intermediate layer in laminated glazings because it has satisfactory energy-absorbing properties and its cost is reduced. However, it is generally not used because its adhesive properties are very weak or non-existent.